Isaac Scientific Publishing

Modern Civil and Structural Engineering

Effects of Strengthening Options in Improving the Lateral Responses of RC Frame Building

Download PDF (904 KB) PP. 44 - 57 Pub. Date: October 26, 2017

DOI: 10.22606/mcse.2017.11004

Author(s)

  • Darpan B. Doshi
    1Structural Engineer, Ashirvad Consultant, Vadodara, India
  • J A. Amin
    Sardar Vallabhbhai Patel Institute of Technology, Vasad-388306, India,

Abstract

During recent past, it was observed that a large number of existing RC frame buildings with irregularities have poor performance or even collapsed during a strong earthquake. Therefore, strengthening of these types of buildings is required because of its inherent irregularities and low resistance against lateral forces. In the present study, efforts were made to investigate and critically assess the effectiveness of some strengthening options in enhancing the seismic performance of typical four storey asymmetric RC frame building using nonlinear static analysis. The different strengthening options studied were infilled RC frames, design of soft storey RC beams and columns by 2.5 times higher design forces as per IS 1893(part 1), design of only soft storey columns by 2.5 times higher design forces, provision of bracing at open ground storey and provision of lateral buttresses in open ground storey. The effect of these strengthening options in improving the ductility as well as lateral strength of asymmetric RC frame building for enhancing seismic behaviour was also studied. The strengthening option suggested by IS: 1893, designing the beams and columns of soft-story for higher forces was found to increase the lateral strength of the RC building 2.29 times as compared to bare RC frame building but it observed ineffective in improving the lateral deformability/ductility of RC frame building. Yield and ultimate lateral strength of the RC frame building with diagonal braces in all bays was found to be the highest, which is 4.31 and 7.12 times higher than the bare RC frame building among all other strengthening option, indicating the most effective strengthening option.

Keywords

RC frame; ductility; pushover analysis; lateral strength

References

[1] IS 1893, “Indian Standard criteria for earthquake resistant design of structures. Part 1: General provisions and buildings,” Bureau of Indian Standards, New Delhi, India, 1984.

[2] IS 1893, “Indian Standard criteria for earthquake resistant design of structures. Part 1: General provisions and buildings,” Bureau of Indian Standards, New Delhi, India, 2002.

[3] EN1998-1, “Design of structures for earthquake resistance-Part 1: General rules, seismic actions and rules for buildings,” European Committee of Standardization, Eurocode 8, Brussels, Belgium. 2004.

[4] IBC, “International Building Code,” International Code Council, 2003.

[5] Antonopoulos, T.A., Anagnostopoulos, S.A., “Optimum partial strengthening for improved seismic performance of old reinforced concrete buildings with open ground story,” Advances in Performance-Based Earthquake Engineering, Geotechnical, Geo-logical, and Earthquake Engineering, M.N. Fardis (ed.), Springer, 13, pp. 395-404, 2010.

[6] Jain S.K., Lettis. W. R., Murty C.V.R., and Bardet, J.P., ed., “Bhuj, India Earthquake of January 26, 2001reconnnaissance report,” Earthquake Spectra, 18(S1), pp. 149-185, 2002.

[7] Dolšek, M., Fajfar, P., “Soft storey effects in uniformly infilled reinforced concrete frames,” Journal of Earthquake Eng., vol. 5(1), pp. 1–12, 2001.

[8] Tamboli Kruti, Amin J.A. (2015), “Evaluation of response reduction factor and ductility factor of RC braced frame,” Journal of Materials and Engineering Structures, vol. 2, pp. 120-129, 2015.

[9] Kaushik H. B., Rai D. C., Jain S. K.., “Effectiveness of some strengthening options for masonry-infilled RC frames with open first story,” Journal of Structural Engineering, ASCE, 135 (8), pp. 925-937, 2009.

[10] Das, S., Nau, J. M., “Seismic design aspects of vertically irregular reinforced concrete buildings.” Earthquake Spectra, vol. 19(3), pp. 455–477, 2003.

[11] Fardis, M. N., Negro, P., Bousias, S. N., and Colombo, A., “Seismic design of open-storey infilled RC buildings.” J. Earthquake Eng., vol. 3(2), pp. 173–197, 1999.

[12] Selvakoodalingam, B., Perumal Pillai, E. B., and Govindan, P., “Strengthening of RC infilled frame with opening,” Concrete Int., vol. 21(11), pp. 37–42, 1999.

[13] Negro, P., Colombo, A., “Irregularities induced by nonstructural masonry panels in framed buildings,” Engineering Structure, vol. 19(7), pp. 576–585, 1997.

[14] Structural Analysis Program (SAP2000) “Advanced, static and dynamic finite element analysis of structures,” Computers and Structures Inc., Berkeley, Calif, 2010.

[15] S 456. “Plain and Reinforced Concrete - Code of Practice,” Bureau of Indian Standards New Delhi, India, 2000.

[16] FEMA 356, “Prestandard and commentary for the rehabilitation of buildings,” Federal Emergency Management Agency, Washington, D.C., 2000.

[17] Park, R., Paulay, T., “Reinforced concrete structures,” Wiley, New York, 1975.

[18] Stafford- smith and Carter, C., “A method of analysis of infilled frames,” proc. Of Institute of Civil Engineering (UK), vol. 44, pp. 31-48, 1969.

[19] SII 413, “Design provisions for earthquake resistance of structures”, Standards Institution of Israel Tel-Aviv, Israel, 1995.